Lens module

ABSTRACT

There is provided a lens module, including: a first lens having positive refractive power, an object-sided surface thereof being convex; a second lens having negative refractive power, an image-sided surface thereof being concave; a third lens having positive refractive power; a fourth lens having negative refractive power, an image-sided surface thereof being convex; and a fifth lens having negative refractive power, an image-sided surface thereof being concave, wherein the fourth lens satisfies Conditional Expression 1, 
     
       
         
           
             
               
                 
                   
                     
                       f 
                        
                       
                           
                       
                        
                       4 
                     
                     f 
                   
                   &lt; 
                   
                     - 
                     3.0 
                   
                 
               
               
                 
                   [ 
                   
                     Conditional 
                      
                     
                         
                     
                      
                     Expression 
                      
                     
                         
                     
                      
                     1 
                   
                   ] 
                 
               
             
           
         
       
         
         
           
             where f is an overall focal distance of an optical system and f4 is a focal distance of the fourth lens.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of Korean Patent Application No.10-2012-0062652 filed on Jun. 12, 2012, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lens module for a camera, and moreparticularly, to a lens module capable of realizing a high-resolutionperformance and a bright optical system.

2. Description of the Related Art

Recent mobile communications terminals have a camera provided therewith,allowing for video communications and photography. In addition, as thefunctionality of cameras included in mobile terminals has graduallyincreased, cameras for a mobile terminal have gradually been required tohave high resolution and high functionality.

However, there is a trend for mobile terminals to be smaller and alighter weight, and thus, there may be a limit in realizing ahighly-functional camera having high-resolution.

In order to solve these limits, recently, the lens of the camera hasbeen formed of plastic having a lighter weight than glass, and 4 or morelenses constituting a lens module have been provided to realize highresolution.

However, an improvement of chromatic aberration is more difficult in alens made of plastic than in a lens made of glass, and also, it isdifficult to realize a relatively bright optical system in the plasticlens as compared to the glass lens.

Meanwhile, Patent Documents 1 and 2 disclose lens modules for realizinga high-resolution camera in the related art.

-   (Patent Document 1) KR2012-018573 A-   (Patent Document 2) KR2007-097369 A

SUMMARY OF THE INVENTION

An aspect of the present invention provides a lens module capable ofrealizing a high-resolution performance and a bright optical system.

According to an aspect of the present invention, there is provided alens module, including: a first lens having positive refractive power,an object-sided surface thereof being convex; a second lens havingnegative refractive power, an image-sided surface thereof being concave;a third lens having positive refractive power; a fourth lens havingnegative refractive power, an image-sided surface thereof being convex;and a fifth lens having negative refractive power, an image-sidedsurface thereof being concave, wherein the fourth lens satisfiesConditional Expression 1,

$\begin{matrix}{\frac{f\; 4}{f} < {- 3.0}} & \left\lbrack {{Conditional}\mspace{14mu} {Expression}\mspace{14mu} 1} \right\rbrack\end{matrix}$

where f is an overall focal distance of an optical system and f4 is afocal distance of the fourth lens.

The first lens and the fourth lens may satisfy Conditional Expression 2,

20<ν₁−ν₄<40  [Conditional Expression 2]

where u1 is an abbe number of the first lens, and u4 is an abbe numberof the fourth lens.

The first lens and the fourth lens may satisfy Conditional Expression 3,

$\begin{matrix}{\frac{f\; 4}{f\; 1} < {- 5.0}} & \left\lbrack {{Conditional}\mspace{14mu} {Expression}\mspace{14mu} 3} \right\rbrack\end{matrix}$

where f1 is a focal distance of the first lens, and f4 is the focaldistance of the fourth lens.

The lens module may satisfy Conditional Expression 4,

$\begin{matrix}{0.5 < \frac{TL}{f} < 2.0} & \left\lbrack {{Conditional}\mspace{14mu} {Expression}\mspace{14mu} 4} \right\rbrack\end{matrix}$

where TL is a distance from the object-sided surface of the first lensto an upper surface of an image sensor, and f is the overall focaldistance of the optical system.

The third lens may have a convex image-sided surface.

The fourth lens may have a meniscus shape.

The fifth lens may have at least one inflection point formed on theimage-sided surface thereof.

According to another aspect of the present invention, there is provideda lens module, including: a first lens having positive refractive power,an object-sided surface thereof being convex; a second lens havingnegative refractive power, an image-sided surface thereof being concave;a third lens having a meniscus shape convex toward an image; a fourthlens having negative refractive power, an image-sided surface thereofbeing convex; and a fifth lens having negative refractive power, animage-sided surface thereof being concave,

wherein the fourth lens satisfies Conditional Expression 1,

$\begin{matrix}{\frac{f\; 4}{f} < {- 3.0}} & \left\lbrack {{Conditional}\mspace{14mu} {Expression}\mspace{14mu} 1} \right\rbrack\end{matrix}$

where f is an overall focal distance of an optical system and f4 is afocal distance of the fourth lens.

The first lens and the fourth lens may satisfy Conditional Expression 2,

20<ν₁−ν₄<40  [Conditional Expression 2]

where u1 is an abbe number of the first lens, and u4 is an abbe numberof the fourth lens.

The first lens and the fourth lens may satisfy Conditional Expression 3,

$\begin{matrix}{\frac{f\; 4}{f\; 1} < {- 5.0}} & \left\lbrack {{Conditional}\mspace{14mu} {Expression}\mspace{14mu} 3} \right\rbrack\end{matrix}$

where f1 is a focal distance of the first lens, and f4 is the focaldistance of the fourth lens.

The lens module may satisfy Conditional Expression 4,

$\begin{matrix}{0.5 < \frac{TL}{f} < 2.0} & \left\lbrack {{Conditional}\mspace{14mu} {Expression}\mspace{14mu} 4} \right\rbrack\end{matrix}$

where TL is a distance from the object-sided surface of the first lensto an upper surface of an image sensor, and f is the overall focaldistance of the optical system.

The third lens may be convex toward the image.

The fifth lens may have at least one inflection point formed on at leastone of an object-sided surface and the image-sided surface thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a structural view of a lens module according to a firstembodiment of the present invention;

FIG. 2 is a graph showing aberration characteristics of the lens moduleof FIG. 1;

FIG. 3 is a structural view of a lens module according to a secondembodiment of the present invention;

FIG. 4 is a graph showing aberration characteristics of the lens moduleof FIG. 3;

FIG. 5 is a structural view of a lens module according to a thirdembodiment of the present invention;

FIG. 6 is a graph showing aberration characteristics of the lens moduleof FIG. 5;

FIG. 7 is a structural view of a lens module according to a fourthembodiment of the present invention;

FIG. 8 is a graph showing aberration characteristics of the lens moduleof FIG. 7;

FIG. 9 is a structural view of a lens module according to a fifthembodiment of the present invention; and

FIG. 10 is a graph showing aberration characteristics of the lens moduleof FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings.

In describing the present invention below, terms indicating componentsof the present invention are named in consideration of functionsthereof. Therefore, the terms should not be understood as limitingtechnical components of the present invention.

For reference, it is to be noted that, in the present specification, theterm “front” refers to a direction toward an object from a lens module,while the term “rear” refers to a direction toward an image sensor froma lens module. In addition, it is to be noted that, in each lens, afirst surface refers to a surface toward an object and a second surfacerefers to a surface adjacent to an image.

FIG. 1 is a structural view of a lens module according to a firstembodiment of the present invention; FIG. 2 is a graph showingaberration characteristics of the lens module of FIG. 1; FIG. 3 is astructural view of a lens module according to a second embodiment of thepresent invention; FIG. 4 is a graph showing aberration characteristicsof the lens module of FIG. 3; FIG. 5 is a structural view of a lensmodule according to a third embodiment of the present invention; FIG. 6is a graph showing aberration characteristics of the lens module of FIG.5; FIG. 7 is a structural view of a lens module according to a fourthembodiment of the present invention; FIG. 8 is a graph showingaberration characteristics of the lens module of FIG. 7; FIG. 9 is astructural view of a lens module according to a fifth embodiment of thepresent invention; and FIG. 10 is a graph showing aberrationcharacteristics of the lens module of FIG. 9.

A lens module 100 according to the present invention may include a firstlens 10, a second lens 20, a third lens 30, a fourth lens 40, and afifth lens 50, and may selectively further include an aperture and afilter member 60, and an image sensor 70. The first lens 10 to the fifthlens 50 may be sequentially disposed from an object (that is, a subjector an object to be photographed) toward an image (that is, the imagesensor).

The first lens 10, the second lens 20, the third lens 30, the fourthlens 40, and the fifth lens 50 may be all formed of plastic. As such,when all the lenses 10, 20, 30, 40 and 50 are formed of plastic, themanufacturing cost of the lens module 100 may be reduced and the lensmodules 100 may be conveniently mass-produced. In addition, when thelenses 10, 20, 30, 40, and 50 are formed of plastic, first and secondsurfaces S1, S2, S3, S4, S5, S6, S7, S8, S9, and S10 of the lenses areeasily processed, and thus, the surfaces of the lenses may be formed tohave a spherical or aspherical shape.

In the lens module 100, the first lens 10 may be disposed closest to theobject.

The first lens 10 may have positive refractive power overall. Inaddition, the first surface S1 of the first lens 10 may be convex towardthe object, and the second surface S2 thereof may be convex toward theimage. In detail, the first surface S1 may be more convex than thesecond surface S2.

At least one of the first surface S1 and the second surface S2 of thefirst lens 10 may be aspherical. However, as needed, both of the firstsurface S1 and the second surface S2 of the first lens 10 may beaspherical.

The second lens 20 may be disposed in the rear of the first lens 10(that is, in the direction toward the image). The second lens 20 mayhave negative refractive power overall, and may be formed of plastic inlike manner to the first lens 10.

The first surface S3 of the second lens 20 may be convex toward theobject, and the second surface S4 thereof may be concave toward theobject. In addition, the second lens 20 may have at least one asphericalsurface. For example, at least one of the first surface S3 and thesecond surface S4 of the second lens 20 may be aspherical. However, asneeded, both of the first surface S3 and the second surface S4 of thesecond lens 20 may be aspherical.

The second lens 20 may have an abbe number satisfying MathematicalExpression 1 below.

ν2<40  [Mathematical Expression 1]

Here, u2 is the abbe number of the second lens.

As such, when the abbe number of the second lens 20 is below 40,chromatic aberration caused by the first lens 10 may be effectivelycorrected. When the abbe number of the second lens 20 is above 40, adifference between an abbe number of the first lens 10 and the abbenumber of the second lens 20 may be reduced (In general, the abbe numberof the first lens 10 is between 50 and 60), such that a chromaticaberration correction effect through the second lens 20 may bedeteriorated. Therefore, the second lens 20 may be manufactured in sucha manner that the abbe number thereof is below 40, as supposed inMathematical Expression 1. The abbe number of the second lens 20 may be20 to 30.

The third lens 30 may be disposed in the rear of the second lens 20. Thethird lens 30 may have positive refractive power overall, and may beformed of plastic. However, as needed, the third lens 30 may havenegative refractive power.

The first surface S5 of the third lens 30 may be concave, and the secondsurface S6 thereof may be convex toward the image. Here, in some cases,the first surface S5 of the third lens 30 may be convex toward theobject (please refer to the third embodiment of the present inventionshown in FIG. 5).

Meanwhile, the second lens 20 and the third lens 30 as described abovemay satisfy Mathematical Expression 2.

$\begin{matrix}{{- 3.0} < \frac{f\; 3}{f\; 2} < {- 0.3}} & \left\lbrack {{Mathematical}\mspace{14mu} {Expression}\mspace{14mu} 2} \right\rbrack\end{matrix}$

Here, f2 is a focal distance of the second lens 20 and f3 is a focaldistance of the third lens 30.

In the lens module, if a value of f3/f2 is below the lower limitaccording to Mathematical Expression 2, the refractive power of thesecond lens may be increased, and thus, it may be difficult tomanufacture the second lens. In the same manner, in the lens module, ifthe value of f3/f2 is above the upper limit according to MathematicalExpression 2, the refractive power of the third lens may be increased,and thus, it may be difficult to manufacture the third lens.

Therefore, it is desirable to satisfy conditions for MathematicalExpression 2 to allow for mass-production of the lens module.

The fourth lens 40 may be disposed in the rear of the third lens 30. Thefourth lens 40 may have negative refractive power, and may be formed ofplastic.

The first surface S7 of the fourth lens 40 may be concave, and thesecond surface S8 thereof may be convex toward the image. In addition,the fourth lens 40 may have a meniscus shape, convex toward the image,overall.

The fourth lens 40 may satisfy Mathematical Expressions 3 to 5.

20<ν1−ν4<40  [Mathematical Expression 3]

Here, u1 is the abbe number of the first lens, and u4 is an abbe numberof the fourth lens.

Mathematical Expression 3 may be a limitation condition with respect tochromatic aberration of the lens module. That is, when a lens modulesatisfying Mathematical Expression 3 is manufactured, the chromaticaberration correction effect may be improved through the first lens 10and the fourth lens 40. However, if a value of u1−u4 is below the lowerlimit according to Mathematical Expression 3, a lens of glass needs tobe used, and thus, unit costs for manufacturing the lens module 100 maybe increased. Unlike this, if the value of u1−u4 is above the upperlimit according to Mathematical Expression 3, the chromatic aberrationcorrection effect may be deteriorated, and thus, it may be difficult tomanufacture a lens module capable of realizing high resolution.

$\begin{matrix}{\frac{f\; 4}{f\; 1} < {- 5.0}} & \left\lbrack {{Mathematical}\mspace{14mu} {Expression}\mspace{14mu} 3} \right\rbrack\end{matrix}$

Here, f1 is a focal distance of the first lens, and f4 is a focaldistance of the fourth lens.

Mathematical Expression 4 may be a limitation condition for limiting therefractive power of the fourth lens 40. That is, if a value of f4/f1 isabove the upper limit according to Mathematical Expression 4, therefractive power of the fourth lens 40 in the lens module may beincreased, and thus, resolution of the lens module 100 may bedeteriorated or an overall length of the lens module 100 (that is, anoverall length of the optical system) may be increased.

$\begin{matrix}{\frac{f\; 4}{f} < {- 3.0}} & \left\lbrack {{Mathematical}\mspace{14mu} {Expression}\mspace{14mu} 5} \right\rbrack\end{matrix}$

Here, f is an overall focal distance of the lens module, and f4 is thefocal distance of the fourth lens.

Mathematical Expression 5 may be a limitation condition for limiting therefractive power of the fourth lens 40, like Mathematical Expression 4.That is, if a value of f4/f is above the upper limit according toMathematical Expression 5, the (negative) refractive power of the fourthlens 40 in the lens module may be increased, and thus, resolution of thelens module 100 may be deteriorated or the overall focal distance of thelens module may become excessively small, so that distortion correctionmay be difficult (or a viewing angle of the lens module may beexcessively large, and thus, a distortion phenomenon may occur).

Therefore, Mathematical Expression 4 and Mathematical Expression 5 allmay need to be satisfied in order to decrease the overall length of thelens module 100.

The fifth lens 50 may be disposed in the rear of the fourth lens 40. Thefifth lens 50 may have negative refractive power, and may be formed ofplastic.

The first surface S9 of the fifth lens 50 may be convex toward theobject at an intersection thereof with an optical axis (C-C) and may beconcave at a peripheral portion thereof based on the optical axis (C-C).In addition, the second surface S10 of the fifth lens 50 may be concaveat an intersection thereof with the optical axis (C-C) and may be convexat a peripheral portion thereof based on the optical axis (C-C). Thatis, at least one inflection point may be formed on the first surface S9and the second surface S10 of the fifth lens 50.

The filter member 60 may be disposed in the rear of the fifth lens 50.Both surfaces of the filter member 60 may flat planes, and may be formedof a material other than plastic. For example, the filter member 60 maybe formed of glass.

The filter member 60 may block infrared light. To achieve this, an IRblocking film may be attached to, or an IR blocking layer may be coatedon, at least one surface of the filter member 60. Meanwhile, the filtermember 60 may be omitted, depending on the type of the lens module 100.

The image sensor 70 may be disposed in the rear of the filter member 60.

The image sensor 70 may convert an image of the object, incident throughthe lenses 10, 20, 30, 40, and 50 into an electric signal. Acharge-coupled device (CCD), complementary metal-oxide-semiconductor(CMOS), or the like, may be used for the image sensor 70, and the imagesensor 70 may be manufactured in the form of chip scale package (CSP).

The aperture (not shown) may be disposed in front of the first lens 10or between the first lens 10 and the second lens 20. However, theaperture may be omitted as needed.

The lens module 100 as described above may satisfy MathematicalExpression 6.

$\begin{matrix}{0.5 < \frac{TL}{f} < 2.0} & \left\lbrack {{Mathematical}\mspace{14mu} {Expression}\mspace{14mu} 6} \right\rbrack\end{matrix}$

Here, TL is an overall length of the optical system (a length from thefirst surface S1 of the first lens to an upper surface of the imagesensor 70), and f is the overall focal distance of the optical system.

Mathematical Expression 6 may be a numerical value for limiting theviewing angle and the length of the lens module. That is, if a value ofTL/f is below the lower limit according to Mathematical Expression 6, itmay be difficult to obtain the viewing angle of the lens module 100. Onthe contrary, if the value of TL/f is above the upper limit according toMathematical Expression 6, the length (that is, TL) of the lens module100 is extended, and thus, it is difficult to manufacture the lensmodule 100 so as to have a small size.

Meanwhile, at least one surface of the first lens 10 to the fourth lens40 may be aspherical. Aspherical coefficients of the lenses may becalculated by using Mathematical Expression 7.

$\begin{matrix}{z = {\frac{{ch}^{2}}{1 + {{SQRT}\left( {1 - {\left( {1 + k} \right)c^{2}h^{2}}} \right)}} + {Ah}^{4} + {Bh}^{6} + {Ch}^{8} + {Dh}^{10} + {Eh}^{12} + {Fh}^{14}}} & \left\lbrack {{Mathematical}\mspace{14mu} {Expression}\mspace{14mu} 7} \right\rbrack\end{matrix}$

Here, c is curvature (1/radius of curvature), h is a radius from thecenter to a specific position in the lens, K is a conic coefficient, Ais a 4^(th)-order coefficient, B is a 6^(th)-order coefficient, C is an8^(th)-order coefficient, D is a 10^(th)-order coefficient, E is an12^(th)-order coefficient, F is a 14^(th)-order coefficient, and Z issag at the specific position.

For reference, K, A, B, C, D, E, and F values for respective embodimentsare shown in Tables 2, 4, 6, 8, and 10.

The lens module 100 as constructed above may realize high resolutionthrough numerical limitations according to Mathematical Expressions 1 to5, and may be miniaturized.

In addition, the lens module 100 may improve brightness of the lensmodule 100 by limiting the focal distance of the fourth lens 40 throughMathematical Expressions 4 and 5.

Tables 1 to 10 below show numeral values in several embodiments of thelens module 100 having the above construction.

First Embodiment

The lens module 100 according to the first embodiment of the presentinvention will be described with reference to FIGS. 1 and 2.

The lens module 100 according to the first embodiment may include thefirst lens 10 having positive refractive power, the second lens 20having negative refractive power, the third lens 30 having positiverefractive power, the fourth lens 40 having negative refractive power,and the fifth lens 50 having negative refractive power.

TABLE 1 Radius of Thickness or Surface No. Curvature Distance RefractiveIndex Abbe No. (v) S1 1.381 0.63 1.544 56.1 S2 8.924 0.09 S3 4.656 0.301.632 23.4 S4 1.988 0.37 S5 −6.107 0.37 1.544 56.1 S6 −2.683 0.42 S7−1.294 0.44 1.635 24 S8 −1.591 0.10 S9 2.674 0.86 1.544 56.1 S10 1.6840.18 S11 Infinity 0.30 1.517 64.2 S12 Infinity 0.71 img Infinity

In the lens module 100 of the present embodiment, the focal distance f1of the first lens 10 is 2.91 mm; the focal distance f2 of the secondlens 20 is −5.68 mm; the focal distance f3 of the third lens 30 is 8.44mm; the focal distance f4 of the fourth lens 40 is −25.61 mm; the focaldistance f5 of the fifth lens 50 is −12.01 mm; the overall focaldistance f is 4.12 mm; and F number (F No.) is 2.40. Meanwhile, TLaccording to the embodiment is 4.77 mm, the smallest among theaccompanying embodiments, together with Embodiment 2.

TABLE 2 Surface No. K A B C D E F S1 −1.857E−01  8.822E−03 2.769E−02−5.482E−02 6.735E−02 −2.650E−03 −3.576E−02  S2  0.000E+00 −1.533E−013.258E−01 −4.407E−01 3.643E−01 −1.995E−01 0.000E+00 S3  0.000E+00−2.557E−01 4.932E−01 −5.532E−01 3.437E−01 −1.596E−01 0.000E+00 S4 3.390E+00 −1.678E−01 2.501E−01 −1.168E−01 −1.009E−01   7.702E−020.000E+00 S5  0.000E+00 −1.242E−01 3.027E−02  5.238E−02 1.532E−01−1.558E−01 −3.302E−02  S6  0.000E+00 −4.577E−02 −2.435E−02   9.005E−028.243E−02 −1.060E−01 1.767E−02 S7 −7.750E+00 −1.172E−01 2.440E−02 3.182E−02 1.992E−02 −4.579E−02 1.490E−02 S8 −7.074E+00 −1.305E−016.054E−02  5.414E−03 −6.086E−03  −1.476E−03 6.415E−04 S9 −1.756E+01−1.810E−01 8.834E−02 −1.984E−02 2.252E−03 −1.045E−04 0.000E+00 S10−8.176E+00 −6.832E−02 1.848E−02 −3.813E−03 4.408E−04 −1.997E−050.000E+00

Second Embodiment

The lens module 100 according to the second embodiment of the presentinvention will be described with reference to FIGS. 3 and 4.

The lens module 100 according to the second embodiment may include thefirst lens 10 having positive refractive power, the second lens 20having negative refractive power, the third lens 30 having positiverefractive power, the fourth lens 40 having negative refractive power,and the fifth lens 50 having negative refractive power.

TABLE 3 Radius of Thickness or Surface No. Curvature Distance RefractiveIndex Abbe No. (v) S1 1.406 0.65 1.544 56.1 S2 11.651 0.09 S3 4.624 0.281.632 23.4 S4 1.950 0.37 S5 −6.459 0.33 1.544 56.1 S6 −2.625 0.33 S7−1.220 0.44 1.635 24 S8 −1.419 0.22 S9 3.379 0.85 1.544 56.1 S10 1.7590.21 S11 Infinity 0.30 1.517 64.2 S12 Infinity 0.70 img Infinity

In the lens module 100 of the present embodiment, the focal distance f1of the first lens 10 is 2.86 mm; the focal distance f2 of the secondlens 20 is −5.50 mm; the focal distance f3 of the third lens 30 is 7.85mm; the focal distance f4 of the fourth lens 40 is −100.00 mm; the focaldistance f5 of the fifth lens 50 is −8.24 mm; the overall focal distancef is 4.12 mm; and F No. is 2.40. In addition, TL according to theembodiment is 4.77, the smallest, together with the first embodiment.

TABLE 4 Surface No. K A B C D E F S1 −1.279E−01  5.285E−03 1.100E−02−2.319E−02 1.870E−02  1.418E−02 −3.576E−02  S2  0.000E+00 −1.403E−013.172E−01 −4.893E−01 4.199E−01 −2.180E−01 0.000E+00 S3  0.000E+00−2.361E−01 4.952E−01 −5.972E−01 3.879E−01 −1.596E−01 0.000E+00 S4 2.060E+00 −1.456E−01 2.874E−01 −1.720E−01 7.661E−03  7.702E−020.000E+00 S5  0.000E+00 −1.194E−01 4.204E−02 −3.706E−02 2.576E−01−1.654E−01 −3.302E−02  S6  0.000E+00 −3.044E−02 7.503E−03 −1.392E−021.149E−01 −3.098E−02 −3.233E−02  S7 −5.304E+00 −8.453E−02 3.411E−02−1.067E−02 2.377E−02 −2.645E−02 5.479E−03 S8 −4.342E+00 −7.572E−023.027E−02  9.316E−03 −4.083E−03  −2.132E−03 6.763E−04 S9 −1.756E+01−1.537E−01 6.951E−02 −1.396E−02 1.386E−03 −5.457E−05 0.000E+00 S10−8.176E+00 −6.808E−02 1.964E−02 −4.242E−03 5.018E−04 −2.250E−050.000E+00

Third Embodiment

The lens module 100 according to the third embodiment of the presentinvention will be described with reference to FIGS. 5 and 6.

The lens module 100 according to the third embodiment may include thefirst lens 10 having positive refractive power, the second lens 20having negative refractive power, the third lens 30 having positiverefractive power, the fourth lens 40 having negative refractive power,and the fifth lens 50 having negative refractive power.

Here, the first surface S5 of the third lens 30 may be convex toward theobject, unlike the other embodiments. In addition, the fourth lens 40may have an inflection point at a peripheral portion based on theoptical axis (C-C) as shown in FIG. 5.

TABLE 5 Radius of Thickness or Surface No. Curvature Distance RefractiveIndex Abbe No. (v) S1 1.436 0.64 1.544 56.1 S2 6.630 0.08 S3 3.358 0.271.632 23.4 S4 1.706 0.45 S5 13.188 0.48 1.544 56.1 S6 −3.790 0.22 S7−1.061 0.33 1.614 25.6 S8 −1.207 0.28 S9 4.924 0.96 1.544 56.1 S10 1.8830.17 S11 Infinity 0.30 1.517 64.2 S12 Infinity 0.70 img Infinity

In the lens module 100 of the present embodiment, the focal distance f1of the first lens 10 is 3.23 mm; the focal distance f2 of the secondlens 20 is −5.85 mm; the focal distance f3 of the third lens 30 is 5.46mm; the focal distance f4 of the fourth lens 40 is −100.00 mm; the focaldistance f5 of the fifth lens 50 is −6.31 mm; and the overall focaldistance f is 4.16 mm. In addition, F No. of the present embodiment is2.20, brighter than the first and second embodiments. However, TLaccording to the embodiment is 4.87, slightly larger than the first andsecond embodiments.

TABLE 6 Surface No. K A B C D E F S1 −4.734E−02  1.039E−02 9.817E−03 1.128E−02 −3.620E−03   3.154E−03 1.005E−02 S2  0.000E+00 −1.480E−013.499E−01 −4.657E−01 4.167E−01 −1.825E−01 −9.593E−11  S3  0.000E+00−2.849E−01 4.791E−01 −5.550E−01 4.056E−01 −1.943E−01 7.842E−11 S4 1.916E+00 −1.879E−01 2.221E−01 −1.494E−01 −3.436E−02   3.671E−025.422E−11 S5  0.000E+00 −5.424E−02 1.372E−02 −1.117E−01 1.591E−01−7.781E−02 −6.676E−03  S6  0.000E+00  2.355E−02 1.825E−02 −9.312E−029.100E−02 −3.215E−02 −2.116E−03  S7 −3.555E+00  3.317E−02 6.449E−02−2.497E−02 1.728E−02 −2.030E−02 5.935E−03 S8 −3.212E+00 −3.105E−025.708E−02  1.093E−02 −6.751E−03  −3.138E−03 1.104E−03 S9 −1.756E+01−1.831E−01 9.539E−02 −3.645E−02 1.111E−02 −1.950E−03 1.375E−04−8.176E+00 −7.204E−02 2.713E−02 −8.822E−03 1.803E−03 −2.120E−041.069E−05

Fourth Embodiment

The lens module 100 according to the fourth embodiment of the presentinvention will be described with reference to FIGS. 7 and 8.

The lens module 100 according to the fourth embodiment may include thefirst lens 10 having positive refractive power, the second lens 20having negative refractive power, the third lens 30 having positiverefractive power, the fourth lens 40 having negative refractive power,and the fifth lens 50 having negative refractive power.

Here, the fourth lens 40 may have an inflection point at the peripheralportion thereof based the optical axis (C-C) like in the thirdembodiment.

TABLE 7 Surface Radius of Thickness or No. Curvature Distance RefractiveIndex Abbe No. (V) S1 1.421 0.64 1.544 56.1 S2 4.647 0.08 S3 3.052 0.251.632 23.4 S4 1.803 0.49 S5 −167.850 0.48 1.544 56.1 S6 −2.394 0.16 S7−0.971 0.36 1.635 24 S8 −1.128 0.43 S9 4.527 0.67 1.544 56.1 S10 1.6730.21 S11 Infinity 0.30 1.517 64.2 S12 Infinity 0.81 img Infinity

In the lens module 100 of the present embodiment, the focal distance f1of the first lens 10 is 3.52 mm; the focal distance f2 of the secondlens 20 is −7.55 mm; the focal distance f3 of the third lens 30 is 4.46mm; the focal distance f4 of the fourth lens 40 is −95.01 mm; the focaldistance f5 of the fifth lens 50 is −5.32 mm; and the overall focaldistance f is 4.21 mm. In addition, F No. and TL according to theembodiment are 2.20 and 4.87, respectively. F No. of the presentembodiment is low, similarly to the case of the third embodiment, but TLaccording to the embodiment is slightly larger as compared with those ofthe first and second embodiments.

TABLE 8 Surface No. K A B C D E F S1 −5.367E−02  8.025E−03 1.514E−02 3.207E−03 −7.845E−03   1.837E−02 0.000E+00 S2  0.000E+00 −1.984E−013.673E−01 −4.480E−01 4.132E−01 −1.994E−01 0.000E+00 S3  0.000E+00−3.320E−01 4.807E−01 −4.276E−01 2.646E−01 −1.515E−01 0.000E+00 S4 2.336E+00 −1.899E−01 2.280E−01 −8.781E−02 −8.228E−02   3.671E−020.000E+00 S5  0.000E+00 −7.394E−02 2.007E−02 −1.709E−01 2.681E−01−1.298E−01 0.000E+00 S6  0.000E+00  5.194E−02 −2.272E−02  −4.804E−028.263E−02 −3.874E−02 0.000E+00 S7 −3.411E+00  4.881E−02 6.940E−02−3.097E−02 1.160E−02 −2.132E−02 8.095E−03 S8 −3.459E+00 −1.721E−044.079E−02  4.433E−03 −6.632E−03  −2.549E−03 1.346E+03 S9 −1.756E+01−1.367E−01 4.374E−02 −6.467E−03 4.294E−04 −7.727E−07 0.000E+00 S10−8.176E+00 −6.509E−02 1.730E−02 −3.737E−03 4.503E−04 −3.085E−058.626E−07

Fifth Embodiment

The lens module 100 according to the fifth embodiment of the presentinvention will be described with reference to FIGS. 9 and 10.

The lens module 100 according to the fifth embodiment may include thefirst lens 10 having positive refractive power, the second lens 20having negative refractive power, the third lens 30 having positiverefractive power, the fourth lens 40 having negative refractive power,and the fifth lens 50 having negative refractive power.

TABLE 9 Surface Radius of Thickness or No. Curvature Distance RefractiveIndex Abbe No. (V) S1 1.637 0.72 1.544 56.1 S2 45.096 0.09 S3 4.687 0.301.632 23.4 S4 1.971 0.40 S5 −20.922 0.43 1.544 56.1 S6 −3.417 0.43 S7−1.297 0.41 1.635 24 S8 −1.491 0.09 S9 3.226 0.98 1.544 56.1 S10 1.6850.20 S11 Infinity 0.30 1.517 64.2 S12 Infinity 0.70 img Infinity

In the lens module 100 of the present embodiment, the focal distance f1of the first lens 10 is 3.09 mm; the focal distance f2 of the secondlens 20 is −5.56 mm; the focal distance f3 of the third lens 30 is 7.41mm; the focal distance f4 of the fourth lens 40 is −91.69 mm; the focaldistance f5 of the fifth lens 50 is −8.34 mm; and the overall focaldistance f is 4.25 mm. In addition, F No. of the present embodiment is2.20, brighter as compared with the first and second embodiments, but TLaccording to the embodiment is 5.05, the greatest among the accompanyingembodiments.

TABLE 10 Surface No. K A B C D E F S1 −3.596E−01  1.165E−03 7.459E−03−2.742E−02 1.868E−02 −4.584E−03 −7.427E−03  S2  0.000E+00 −1.559E−013.396E−01 −4.891E−01 3.692E−01 −1.290E−01 0.000E+00 S3  0.000E+00−2.524E−01 5.538E−01 −6.911E−01 5.115E−01 −1.753E−01 0.000E+00 S4 1.265E+00 −1.673E−01 3.220E−01 −3.118E−01 2.376E−01 −8.550E−020.000E+00 S5  0.000E+00 −1.078E−01 3.365E−02 −5.060E−03 1.153E−01−7.499E−02 8.252E−03 S6  0.000E+00 −4.706E−02 −2.680E−02   7.909E−02−3.231E−02   2.626E−02 −1.321E−02  S7 −7.540E+00 −7.308E−02 1.782E−02 6.047E−03 1.635E−02 −1.995E−02 4.378E−03 S8 −6.736E+00 −8.506E−022.676E−02  1.017E−02 −2.270E−03  −2.827E−03 7.803E−04 S9 −1.756E+01−7.900E−01 3.000E−01 −7.265E−02 1.000E−02  1.450E−03 0.000E+00 S10−8.176E+00 −1.048E+00 7.922E−02 −1.488E−02 7.258E−03  2.992E−040.000E+00

Table 11 shows main numerical values for the above-describedembodiments.

All of the above-described embodiments 1 to 5 satisfy numericallimitations according to Mathematical Expressions 1 to 5, as shown inTable 11.

Here, the first and second embodiments may provide a relatively smallerTL than the other embodiments, while the third to fifth embodiments mayprovide a relatively brighter lens module than the other embodiments.

TABLE 11 Third Fourth Fifth First Second Embodi- Embodi- Embodi- NoteEmbodiment Embodiment ment ment ment f 4.12 4.12 4.16 4.21 4.25 BFL 1.201.21 1.17 1.32 1.20 F No. 2.40 2.40 2.20 2.20 2.20 TL 4.77 4.77 4.874.87 5.05 FOV 70.00 70.20 70.40 69.70 69.10 f1 2.91 2.86 3.23 3.52 3.09f2 −5.68 −5.50 −5.85 −7.55 −5.56 f3 8.44 7.85 5.46 4.46 7.41 f4 −25.61−100.00 −100.00 −95.01 −91.69 f5 −12.01 −8.24 −6.31 −5.32 −8.34 f4/f−6.22 −24.27 −24.04 −22.57 −21.57 v1 − v4 32.10 32.10 30.50 32.10 32.10f3/f2 −1.49 −1.43 −0.93 −0.59 −1.33 f4/f1 −8.82 −34.95 −30.98 −27.01−29.66 TL/f 1.16 1.16 1.17 1.16 1.19 v2 23.40 23.40 23.40 23.40 23.40

As set forth above, the lens module capable of realizing ahigh-resolution camera and a bright optical system can be provided.

While the present invention has been shown and described in connectionwith the embodiments, it will be apparent to those skilled in the artthat modifications and variations can be made without departing from thespirit and scope of the invention as defined by the appended claims.

1-13. (canceled)
 14. A lens module, comprising a first lens havingpositive refractive power and comprising a convex surface on an objectside; a second lens having negative refractive power and comprising anobject-sided surface being convex in the center and concave at theperiphery and an concave surface on an image side; a third lens havingpositive refractive power and comprising a biconvex shape; a fourth lenscomprising a concave surface on the object side and a convex surface onthe image side; a fifth lens having negative refractive power andcomprising: an object-sided surface being convex in the center andconcave at the periphery; and an image-sided surface being concave inthe center and convex at the periphery; and an aperture disposed betweenthe first lens and the second lens, wherein the first lens, the secondlens, the third lens, the fourth lens and the fifth lens are arranged inorder from an object side to an image side.
 15. The lens module of claim14, wherein the convex surfaces of the first and fourth lenses, thebiconvex shape of the third lens, and the concave surfaces of the secondand fourth lenses are arranged on an optical axis.
 16. The lens moduleof claim 15, wherein: the first lens and the second lens are aspherical,the fourth lens has a meniscus shape, and the fifth lens has at leastone inflection point formed on object-sided and image-sided surfacesthereof.
 17. The lens module of claim 15, wherein: the abbe number ν2 ofthe second lens satisfies the following condition expression:20≦ν2≦30, and an abbe number ν1 of the first lens and an abbe number ν4of the fourth lens satisfy the following conditional expression:20<ν₁−ν₄<40.
 18. The lens module of claim 15, wherein: an abbe number ofthe second lens is about 23.4, abbe numbers of the first and thirdlenses are about 56.1, and an abbe number of the fourth lens is about24.
 19. The lens module of claim 15, wherein the lens module satisfiesthe following conditional expression: $0.5 < \frac{TL}{f} < 2.0$ whereTL is a distance on the optical axis between an object-side surface ofthe first lens and an image sensor, and f is the overall focal distanceof the optical system.
 20. The lens module of claim 15, wherein a focaldistance of the second lens f2 and a focal distance of the third lens f3satisfy the following conditional expression:${- 3.0} < \frac{f\; 3}{f\; 2} < {- {0.3.}}$
 21. The lens module ofclaim 15, further comprising: a filter disposed in a rear of the fifthlens to block infrared light; and an image sensor disposed in a rear ofthe filter, wherein the first lens, the second lens, the third lens, thefourth lens and the fifth lens are made of plastic.
 22. The lens moduleof claim 15, wherein the lens module satisfies the following conditionalexpression:|f2|>f where f2 is a focal distance of the second lens, and f is theoverall focal distance of the lens module.
 23. The lens module of claim15, wherein a radius r1 of curvature of an object-side surface of thefirst lens and a radius r4 of curvature of an image-side surface of thesecond lens satisfy the following conditional expression:r4>r1.
 24. The lens module of claim 15, wherein the lens modulesatisfies the following conditional expression:(r1+d12)>|r8| where r1 is a radius of curvature of an object-sidesurface of the first lens, r8 is a radius of curvature of an image-sidesurface of the fourth lens, and d12 is a distance from an image-sidesurface of the first lens to an object-side surface of the second lens.25. The lens module of claim 15, wherein the lens module satisfies thefollowing conditional expression:(|r7|+d42)>|r8| where r7 is a radius of curvature of an object-sidesurface of the fourth lens, r8 is a radius of curvature of an image-sidesurface of the fourth lens, and d42 is a distance from the image-sidesurface of the fourth lens to an object-side surface of the fifth lens.26. The lens module of claim 15, wherein the lens module satisfies thefollowing conditional expression:TL/f1<1.88 where TL is a distance on the optical axis between anobject-side surface of the first lens and an image sensor, and f1 is afocal distance of the first lens.
 27. The lens module of claim 15,wherein the lens module satisfies the following conditional expression:TL/f5<−0.30 where TL is a distance on the optical axis between anobject-side surface of the first lens and an image sensor, and f5 is afocal distance of the fifth lens.
 28. The lens module of claim 15,wherein the lens module satisfies the following conditional expression:$1.103 < \frac{r\; 2}{f} < 10.611$ wherein a radius r2 of curvature ofan image-side surface of the first lens, and f is the overall focaldistance of the lens module.
 29. The lens module of claim 15, whereinthe lens module satisfies the following conditional expression:$0.649 < \frac{r\; 9}{f} < 1.184$ where r9 is a radius of curvature ofan object-side surface of the fifth lens, and f is the overall focaldistance of the lens module.
 30. The lens module of claim 15, whereinthe lens module satisfies the following conditional expression:$0.080 < \frac{{ct}\; 3}{f} < 0.116$ where ct3 is a thickness of thethird lens, and f is the overall focal distance of the lens module. 31.The lens module of claim 15, wherein the lens module satisfies thefollowing conditional expression: $0.079 < \frac{{ct}\; 4}{f} < 0.107$where ct4 is a thickness of the fourth lens, and f is the overall focaldistance of the lens module.
 32. The lens module of claim 15, whereinthe lens module satisfies the following conditional expression:$1.587 < \frac{r\; 9}{r\; 10} < 2.706$ where r9 is a radius ofcurvature of an object-side surface of the fifth lens, and r10 is aradius of curvature of an image-side surface of the fifth lens.
 33. Thelens module of claim 15, wherein the lens module satisfies the followingconditional expression:$2.172 < \frac{{r\; 9} + {r\; 10}}{{r\; 9} - {r\; 10}} < 4.403$where r9 is a radius of curvature of an object-side surface of the fifthlens, and r10 is a radius of curvature of an image-side surface of thefifth lens.
 34. The lens module of claim 15, wherein the lens modulesatisfies the following conditional expression:$2.451 < \frac{{r\; 3} + {r\; 4}}{{r\; 3} - {r\; 4}} < 3.888$where r3 is a radius of curvature of an object-side surface of thesecond lens, and r4 is a radius of curvature of an image-side surface ofthe second lens.
 35. The lens module of claim 15, wherein a distance d34from an image-side surface of the third lens to an object-side surfaceof the fourth lens satisfies the following conditional expression:0.16≦d34≦0.43.
 36. The lens module of claim 15, wherein the lens modulesatisfies the following conditional expression:$0.038 < \frac{d\; 34}{f} < 0.102$ where d34 is a distance from animage-side surface of the third lens to an object-side surface of thefourth lens, and f is the overall focal distance of the lens module. 37.The lens module of claim 15, wherein a thickness ct3 of the third lensand a thickness ct4 of the fourth lens satisfy the following conditionalexpression:0.33≦ct3≦0.480.33≦ct4≦0.44.
 38. The lens module of claim 15, wherein a radius r1 ofcurvature of an object-side surface of the first lens, a radius r2 ofcurvature of an image-side surface of the first lens, a radius r7 ofcurvature of an object-side surface of the fourth lens, a radius r8 ofcurvature of an image-side surface of the fourth lens, and a radius r9of curvature of an object-side surface of the fifth lens satisfy thefollowing conditional expression:1.381≦r1≦1.6374.647≦r2≦45.096−1.297≦r7≦−0.971−1.591≦r8≦−1.1282.674≦r9≦4.924.
 39. The lens module of claim 15, wherein a focaldistance f4 of the fourth lens satisfies the following conditionalexpression:25.61≦|f4≦100.
 40. The lens module of claim 15, wherein the lens modulesatisfies the following conditional expression:$2.132 < {\frac{f\; 4}{f\; 5}} < 17.860$ where f4 is a focaldistance of the fourth lens, and f5 a focal distance of the fifth lens.41. The lens module of claim 15, wherein the lens module satisfies thefollowing conditional expression:$1.482 < {\frac{r\; 5}{f\;}} < 39.870$ Where r5 is a radius ofcurvature of an object-side surface of the third lens, and f is theoverall focal distance of the lens module.
 42. The lens module of claim15, wherein the lens module satisfies the following conditionalexpression: $2.276 < {\frac{r\; 5}{r\; 6}} < 70.113$ where r5 is aradius of curvature of an object-side surface of the third lens, and r6is a radius of curvature of an image-side surface of the third lens. 43.The lens module of claim 15, wherein an Abbe number of the fourth lensis different from Abbe numbers of the first, third and fifth lenses.